CN112272809A - Flow rate control method and flow rate control device - Google Patents
Flow rate control method and flow rate control device Download PDFInfo
- Publication number
- CN112272809A CN112272809A CN201980032448.2A CN201980032448A CN112272809A CN 112272809 A CN112272809 A CN 112272809A CN 201980032448 A CN201980032448 A CN 201980032448A CN 112272809 A CN112272809 A CN 112272809A
- Authority
- CN
- China
- Prior art keywords
- control valve
- flow rate
- pressure
- control
- pressure sensor
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000000034 method Methods 0.000 title claims abstract description 47
- 238000011144 upstream manufacturing Methods 0.000 claims abstract description 86
- 239000012530 fluid Substances 0.000 claims abstract description 50
- 230000008859 change Effects 0.000 claims description 25
- 230000007423 decrease Effects 0.000 claims description 12
- 230000001419 dependent effect Effects 0.000 claims 1
- 239000007789 gas Substances 0.000 description 38
- 230000008569 process Effects 0.000 description 6
- 230000009467 reduction Effects 0.000 description 5
- 238000004364 calculation method Methods 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 4
- 239000004065 semiconductor Substances 0.000 description 4
- 230000004043 responsiveness Effects 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- 238000013459 approach Methods 0.000 description 2
- 238000000231 atomic layer deposition Methods 0.000 description 2
- 238000012937 correction Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 238000003860 storage Methods 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 229910052786 argon Inorganic materials 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 238000004590 computer program Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 230000006870 function Effects 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
- G05D7/00—Control of flow
- G05D7/06—Control of flow characterised by the use of electric means
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
- G05D7/00—Control of flow
- G05D7/06—Control of flow characterised by the use of electric means
- G05D7/0617—Control of flow characterised by the use of electric means specially adapted for fluid materials
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
- G01F1/05—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects
- G01F1/34—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects by measuring pressure or differential pressure
- G01F1/36—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects by measuring pressure or differential pressure the pressure or differential pressure being created by the use of flow constriction
- G01F1/363—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects by measuring pressure or differential pressure the pressure or differential pressure being created by the use of flow constriction with electrical or electro-mechanical indication
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
- G01F1/05—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects
- G01F1/34—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects by measuring pressure or differential pressure
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F15/00—Details of, or accessories for, apparatus of groups G01F1/00 - G01F13/00 insofar as such details or appliances are not adapted to particular types of such apparatus
- G01F15/001—Means for regulating or setting the meter for a predetermined quantity
- G01F15/003—Means for regulating or setting the meter for a predetermined quantity using electromagnetic, electric or electronic means
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F15/00—Details of, or accessories for, apparatus of groups G01F1/00 - G01F13/00 insofar as such details or appliances are not adapted to particular types of such apparatus
- G01F15/005—Valves
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
- G05D7/00—Control of flow
- G05D7/06—Control of flow characterised by the use of electric means
- G05D7/0617—Control of flow characterised by the use of electric means specially adapted for fluid materials
- G05D7/0629—Control of flow characterised by the use of electric means specially adapted for fluid materials characterised by the type of regulator means
- G05D7/0635—Control of flow characterised by the use of electric means specially adapted for fluid materials characterised by the type of regulator means by action on throttling means
- G05D7/0641—Control of flow characterised by the use of electric means specially adapted for fluid materials characterised by the type of regulator means by action on throttling means using a plurality of throttling means
- G05D7/0647—Control of flow characterised by the use of electric means specially adapted for fluid materials characterised by the type of regulator means by action on throttling means using a plurality of throttling means the plurality of throttling means being arranged in series
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
- F16K31/00—Actuating devices; Operating means; Releasing devices
- F16K31/004—Actuating devices; Operating means; Releasing devices actuated by piezoelectric means
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- Engineering & Computer Science (AREA)
- Automation & Control Theory (AREA)
- Electromagnetism (AREA)
- Flow Control (AREA)
Abstract
The invention provides a flow control method when the flow rate is increased by using a flow control device (100), wherein the flow control device (100) comprises: a first control valve (6) provided in the flow path; a second control valve (8) disposed on the downstream side of the first control valve; and a pressure sensor (3) that measures the fluid pressure on the downstream side of the first control valve and on the upstream side of the second control valve, the flow rate control method including: (a) a step of obtaining a pressure remaining downstream of the first control valve using a pressure sensor in a state where the second control valve is closed; and (b) controlling a pressure remaining downstream of the first control valve by adjusting an opening degree of the second control valve based on an output of the pressure sensor, and flowing the fluid at a first flow rate downstream of the second control valve.
Description
Technical Field
The present invention relates to a flow rate control method and a flow rate control device, and more particularly, to a flow rate control method and a flow rate control device which can be suitably used in a semiconductor manufacturing apparatus, a chemical plant (facility), or the like.
Background
In semiconductor manufacturing apparatuses and chemical plants, various types of flow meters and flow rate control apparatuses are used to control the flow of fluids such as material gases and etching gases. Among them, the pressure type flow rate control device is widely used because it can control the flow rate of various fluids with high accuracy by a relatively simple mechanism in which a control valve and a throttling portion (for example, an orifice plate) are combined. The pressure type flow rate control device has excellent flow rate control characteristics that enable stable flow rate control even when the primary side supply pressure varies greatly. For example, patent document 1 discloses a pressure type flow rate control device.
As a control valve used for a pressure type flow rate control device, a piezoelectric element driven valve in which a metal diaphragm valve element is opened and closed by a piezoelectric element driving device (hereinafter, may be referred to as a piezoelectric actuator) is used. Patent document 2 discloses a normally open piezoelectric element driven valve used as a control valve.
The pressure type flow rate control device is configured to: the flow rate is adjusted by controlling the fluid pressure on the upstream side of the throttle portion (hereinafter, sometimes referred to as an upstream pressure). The upstream pressure can be controlled by adjusting the opening degree of a control valve provided on the upstream side of the throttle portion, and the fluid can flow at a desired flow rate by matching the upstream pressure to a pressure corresponding to the desired flow rate.
Documents of the prior art
Patent document
Patent document 1: japanese patent laid-open No. 2007-192269
Patent document 2: japanese patent No. 4933936
Patent document 3: japanese patent laid-open No. 2015-138338
Patent document 4: international publication No. 2018/021277
Patent document 5: international publication No. 2018/008420
Patent document 6: international publication No. 2013/179550
A conventional pressure type flow rate control device includes an opening/closing valve provided on a downstream side of a flow hole or an upstream side near the flow hole, and controls the opening/closing of the opening/closing valve. Such a downstream-side on-off valve is used, for example, to stop the supply of gas to the process chamber (process chamber). In addition, even when ALD (Atomic Layer Deposition) processing is performed using a pressure type flow rate control device, pulse type flow rate control with a short cycle is performed by repeating opening and closing operations of the downstream side opening and closing valve.
However, even after the flow rate is set to zero by closing the control valve and the downstream on-off valve, the flow path internal pressure may increase due to a slight leakage of the fluid passing through the control valve. Further, depending on the time when the control valve and the downstream opening/closing valve are closed, the pressure of the fluid flowing before the valve is closed may remain between the valves after the valve is closed, and a relatively high pressure may remain. As a result, when the flow rate control is restarted, the flow path internal pressure increases, and therefore, when the downstream opening/closing valve is opened, the remaining pressure is released to the downstream side at a stroke, and there is a problem that a so-called overshoot (overshoot) occurs in the control flow rate at the time of the rise (start).
As a technique for preventing overshoot when the flow rate rises, patent document 3 discloses that an exhaust line is provided between a control valve and an orifice, and exhaust is performed before the flow rate control, thereby reducing the upstream pressure. However, in the system described in patent document 3, it is necessary to separately provide the exhaust pipe and the on-off valve for the exhaust pipe, and there is a problem that an increase in cost and an increase in size of the apparatus cannot be avoided. Even if the exhaust gas is discharged before the flow rate control, in the method of feedback-controlling the opening degree of the control valve based on the upstream pressure, it may be difficult to sufficiently improve the responsiveness when the flow rate is increased.
Disclosure of Invention
The present invention has been made in view of the above problems, and a main object thereof is to provide a flow rate control method and a flow rate control device capable of preventing overshoot when a flow rate rises, improving responsiveness, and quickly controlling a set flow rate.
A flow rate control method according to an embodiment of the present invention is a flow rate control method performed when a flow rate increases from a flow rate zero to a first flow rate using a flow rate control device, the flow rate control device including: a first control valve provided in the flow path; a second control valve provided downstream of the first control valve; and a pressure sensor that measures a fluid pressure on a downstream side of the first control valve and on an upstream side of the second control valve, the flow rate control method including: a step (a) of obtaining a pressure remaining downstream of the first control valve based on an output of the pressure sensor in a state where the second control valve is closed; and a step (b) of controlling a pressure remaining downstream of the first control valve by adjusting an opening degree of the second control valve based on an output of the pressure sensor, and flowing a fluid at the first flow rate downstream of the second control valve.
In one embodiment, in the step (a), the residual pressure is obtained in a state where both the first control valve and the second control valve are closed.
In one embodiment, the flow rate control method further includes: and (c) a step of opening the first control valve until a pressure remaining downstream of the first control valve becomes higher than a pressure corresponding to the first flow rate and closing the first control valve at a time point when the pressure corresponding to the first flow rate is exceeded, when the pressure obtained based on the output of the pressure sensor is lower than the pressure corresponding to the first flow rate in the step (a).
In one embodiment, in the step (a), the first control valve is closed to an opening degree smaller than an opening degree at which the opening degree of the first control valve is controlled to the first flow rate based on the output of the pressure sensor, and the second control valve is opened to perform the step (b) when a pressure obtained based on the output of the pressure sensor is equal to or greater than a threshold value.
In one embodiment, in the step (b), when α is a proportional constant, Δ P1/Δ t is a pressure change rate which is a ratio of a time Δ t required for a change Δ P1 in the upstream pressure to a change Δ P1 in the upstream pressure outputted by the pressure sensor, and V is an internal volume between the first control valve and the second control valve, the opening degree of the second control valve is controlled based on a signal outputted by the pressure sensor so that a reduced (build-down) flow rate Q represented by Q · (Δ P1/Δ t) · V matches the first flow rate.
In one embodiment, the flow rate control method further includes: and (c) controlling the opening degree of the first control valve based on the output of the pressure sensor at a point of time when the output of the pressure sensor decreases to a predetermined value after the step (b) is performed, and flowing the fluid at the downstream side at the first flow rate.
A flow rate control device according to an embodiment of the present invention includes: a first control valve provided in the flow path; a second control valve provided downstream of the first control valve; a pressure sensor that measures a fluid pressure on a downstream side of the first control valve and on an upstream side of the second control valve; and a control circuit that controls operations of the first control valve and the second control valve, and is configured to: the control circuit controls the flow rate by controlling the first control valve and the second control valve based on a signal output from the pressure sensor, and when the flow rate is increased from zero to a first flow rate, the control circuit executes: a step (a) of obtaining a pressure remaining downstream of the first control valve based on an output of the pressure sensor in a state where the second control valve is closed; and a step (b) of controlling a pressure remaining downstream of the first control valve by adjusting an opening degree of the second control valve based on an output of the pressure sensor, and flowing a fluid at a first flow rate downstream of the second control valve.
In one embodiment, the flow rate control device further includes: and an additional pressure sensor disposed on a downstream side of the second control valve.
A flow rate control device according to an embodiment of the present invention includes: a first control valve provided in the flow path; a second control valve provided downstream of the first control valve; and a pressure sensor that measures a fluid pressure on a downstream side of the first control valve and on an upstream side of the second control valve, and controls an opening degree of the second control valve based on an output of the pressure sensor such that a rate of change of a pressure remaining downstream of the first control valve matches a rate of change of a pressure when a flow rate when the flow rate is discharged from the second control valve becomes the first flow rate, from a state in which the second control valve is closed and the flow rate is zero, when a control flow rate is changed from a state in which the flow rate is zero to the first flow rate.
In one embodiment, the first control valve is closed when the control flow rate is from the zero flow rate state to the first flow rate state.
In one embodiment, the first control valve is controlled to have an opening degree smaller than an opening degree corresponding to the first flow rate when the control flow rate is from a state in which the flow rate is zero to the first flow rate.
In one embodiment, when α is a proportional constant, Δ P1/Δ t is a pressure change rate which is a ratio of a time Δ t required for a change Δ P1 in the upstream pressure output by the pressure sensor to a time Δ P1 required for the change Δ P1 in the upstream pressure, and V is an internal volume between the first control valve and the second control valve, the opening degree of the second control valve is feedback-controlled based on a signal output by the pressure sensor so that a reduced flow rate Q indicated by Q ═ α · (Δ P1/Δ t) · V coincides with the first flow rate.
In one embodiment, the flow rate control device further includes: and another pressure sensor provided on the downstream side of the second control valve.
A flow rate control device according to an embodiment of the present invention includes: a first control valve provided in the flow path; a second control valve provided downstream of the first control valve; and a first pressure sensor that measures an upstream pressure that is a fluid pressure on a downstream side of the first control valve and on an upstream side of the second control valve, and is configured to: the flow rate on the downstream side is controlled based on the signal output from the first pressure sensor, and when the control flow rate reaches the first flow rate from a state in which the flow rate is zero, the flow rate is controlled based on Q ═ α · (Δ P1/Δ t) · V using the pressure remaining downstream of the first control valve, and the switching is made based on Q ═ K at the time point when the pressure of the first pressure sensor reaches a predetermined pressure1P1, where Q is a flow rate, α is a proportional constant, Δ P1/Δ t is a pressure change rate of the upstream pressure, V is an internal volume between the first control valve and the second control valve, and K is an internal volume between the first control valve and the second control valve1P1 is the upstream pressure output from the first pressure sensor, as a constant depending on the type of fluid and the temperature of the fluid.
In one embodiment, the pressure at the first pressure sensor is based on Q ═ K1At the time of the pressure corresponding to the first flow rate in the control of P1, the control is switched.
A flow rate control device according to an embodiment of the present invention includes: a first control valve provided in the flow path; a second control valve provided downstream of the first control valve; a first pressure sensor that measures an upstream pressure that is a fluid pressure on a downstream side of the first control valve and on an upstream side of the second control valve; and a second pressure sensor that measures a downstream pressure that is a fluid pressure on a downstream side of the second control valve, and is configured to: the flow rate on the downstream side is controlled based on the signals output from the first pressure sensor and the second pressure sensor, and when the control flow rate reaches the first flow rate from a state in which the flow rate is zero, the flow rate is controlled based on ═ α · (Δ P1/Δ t) · V using the pressure remaining downstream of the first control valve, and at a time point when the pressures based on the first pressure sensor and the second pressure sensor reach a predetermined pressure, the switching is made such that the switching is made based on Q ═ K2·P2m(P1-P2)nWhere Q is a flow rate, α is a proportional constant, Δ P1/Δ t is a pressure change rate of the upstream pressure, V is an internal volume between the first control valve and the second control valve, and K is an internal volume between the first control valve and the second control valve2P1 is the upstream pressure, P2 is the downstream pressure output by the second pressure sensor, and m and n are indices derived based on the actual flow rate, as constants depending on the type of fluid and the temperature of the fluid.
In one embodiment, the pressure at the first and second pressure sensors is based on Q ═ K2·P2m(P1-P2)nThe control of (3) is switched to a point of time corresponding to the pressure of the first flow rate.
A flow rate control method according to an embodiment of the present invention is a flow rate control method performed when changing a flow rate from zero to a first flow rate exceeding zero using a flow rate control device, the flow rate control device including: a first control valve capable of adjusting an opening degree, the first control valve being provided in the flow path; a second control valve capable of adjusting an opening degree, the second control valve being provided on a downstream side of the first control valve; a throttle portion having a fixed opening degree, the throttle portion being provided on a downstream side of the first control valve; and a pressure sensor that measures a fluid pressure on a downstream side of the first control valve and on an upstream side of the second control valve or the throttle portion, wherein the flow rate control method includes: a step (a) of causing the fluid between the first control valve and the second control valve to flow at the first flow rate on a downstream side of the second control valve by adjusting an opening degree of the second control valve based on an output of the pressure sensor from a state in which the first control valve and the second control valve are closed and a flow rate is zero; and (b) opening the first control valve at a point in time when the output of the pressure sensor decreases to a predetermined value after the step (a), and flowing a fluid at the first flow rate on the downstream side of the throttle section by controlling the opening degree of the first control valve based on the output of the pressure sensor.
In one embodiment, the throttle portion is provided integrally with the second control valve to constitute an orifice built-in valve.
Effects of the invention
According to an embodiment of the present invention, a flow rate control method and a flow rate control device are provided which can prevent overshoot and can shorten the rise time when the flow rate rises.
Drawings
Fig. 1 is a schematic diagram showing a configuration of a flow rate control device according to an embodiment of the present invention.
Fig. 2 is a diagram for explaining a flow rate control method at the time of a flow rate decrease (step-down) according to the embodiment of the present invention, where (a) is a graph showing a set flow rate, (b) is a graph showing a control flow rate, (c) is a graph showing an upstream pressure P1, (d) is a graph showing a first control valve driving voltage, and (e) and (f) are graphs showing a second control valve driving voltage.
Fig. 3 is a flowchart showing a flow control method according to an embodiment of the present invention.
Description of the symbols
1 flow path
2 throttling part
3 first pressure sensor
4 second pressure sensor
5 temperature sensor
6 first control valve
7 control circuit
8 second control valve
9-flow-hole built-in valve
100 flow control device
Detailed Description
Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the embodiments described below.
Fig. 1 shows a flow rate control device 100 used for performing a flow rate control method according to an embodiment of the present invention. The flow rate control device 100 includes: a first control valve 6, the first control valve 6 being provided in a flow path 1 of a gas G0 connected to a gas supply source, not shown; a throttle section 2, the throttle section 2 being provided on the downstream side of the first control valve 6; a second control valve 8, the second control valve 8 being provided downstream of the first control valve 6 and the throttle section 2; and a first pressure sensor (or upstream pressure sensor) 3 and a temperature sensor 5, wherein the first pressure sensor (or upstream pressure sensor) 3 and the temperature sensor 5 detect the pressure (upstream pressure P1) and the gas temperature T of the fluid between the first control valve 6 and the throttle portion 2, respectively.
The flow rate control device 100 of the present embodiment further includes: and a second pressure sensor (or downstream pressure sensor) 4 for measuring a pressure (downstream pressure P2) on the downstream side of the second control valve 8. The first pressure sensor 3 can measure an upstream pressure P1, which is a fluid pressure between the first control valve 6 and the throttle section 2, and the second pressure sensor 4 can measure a downstream pressure P2, which is a pressure on the downstream side of the second control valve 8. However, in another embodiment, the flow rate control device 100 may not include the second pressure sensor 4 and the temperature sensor 5.
In the present embodiment, the throttle portion 2 and the second control valve 8 are integrally formed as the orifice built-in valve 9, and the throttle portion 2 and the valve body of the second control valve 8 are disposed in close proximity. In this case, unlike the above-described embodiment, the throttle portion 2 may be disposed downstream of the valve element of the second control valve 8. In the case where the throttle section 2 is disposed downstream of the valve body of the second control valve 8, the first pressure sensor 3 measures the upstream pressure P1, which is the fluid pressure between the first control valve 6 and the second control valve 8.
Further, in the case where the second control valve 8 has the throttle portion 2 on the upstream side thereof as in the present embodiment, the upstream pressure P1, which is the fluid pressure between the first control valve 6 and the throttle portion 2, is measured during flow rate control, but when the first control valve 6 and the second control valve 8 are closed, the upstream side of the throttle portion 2 (from the first control valve 6 to the throttle portion 2) and the downstream side of the throttle portion 2 (from the throttle portion 2 to the second control valve 8) become the same pressure, and therefore, the first pressure sensor 3 measures the fluid pressure between the first control valve 6 and the second control valve 8.
The first pressure sensor 3 may be configured as follows: the fluid pressure on the downstream side of the first control valve 6 and the upstream side of the second control valve 8 may be measured between the first control valve 6 and the throttle section 2, or between the first control valve 6 and the second control valve 8.
The flow rate control device 100 further includes: and a control circuit 7 connected to the first control valve 6 and the second control valve 8. The control circuit 7 is configured to: the flow rate is controlled by controlling the opening degree of the first control valve 6 based on the signal output from the first pressure sensor 3, and when the flow rate increases, the opening degree of the second control valve 8 is controlled based on the signal output from the first pressure sensor 3. In the illustrated embodiment, one control circuit 7 is provided in common to both the first control valve 6 and the second control valve 8, but the present invention is not limited to this, and it is needless to say that separate control circuits may be provided for the first control valve 6 and the second control valve 8.
The control circuit 7 may be built in the flow rate control apparatus 100 or may be provided outside the flow rate control apparatus 100. The control circuit 7 is typically a memory (storage device) having a processor such as a CPU, a ROM, a RAM, or the like, an a/D converter, or the like incorporated therein, and may include a computer program configured to execute a flow rate control operation described later. The control circuit 7 may be implemented by a combination of hardware and software.
The control circuit 7 may be provided with an interface for exchanging information with an external device such as a computer, and thus, programs, data, and the like can be written from the external device to the ROM. The components (such as the CPU) of the control circuit 7 need not all be provided integrally in the apparatus, but may be configured by arranging some of the components (such as the CPU) in another place (outside the apparatus) and connecting them to each other by a bus (bus). In this case, the inside and outside of the device can communicate not only by wire but also by wireless.
The downstream side of the flow rate control device 100 configured as described above is connected to a process chamber of a semiconductor manufacturing apparatus via, for example, a downstream valve not shown. A vacuum pump is connected to the process chamber, and typically, a gas G1 whose flow rate is controlled by the flow rate control device 100 is supplied to the process chamber in a state where the interior of the process chamber is evacuated. As the downstream Valve, for example, a known Air-Operated Valve (Air Operated Valve) whose opening and closing operations are controlled by compressed Air, or an on-off Valve (opening and closing Valve) such as an electromagnetic Valve can be used.
In the present embodiment, the throttle portion 2 is formed of an orifice plate. The orifice plate functions as a throttle portion having a fixed opening degree because the orifice cross-sectional area is fixed. In addition, although the orifice area may be unexpectedly changed due to clogging of the orifice, deterioration with age, or the like, in the present specification, a throttle portion that is not configured to intentionally control the opening degree is referred to as a fixed-opening throttle portion. In the present specification, the term "throttle portion" refers to a portion that limits the cross-sectional area of the flow path to be smaller than the cross-sectional areas of the flow paths in the front and rear directions, and is configured using, for example, a flow orifice plate, a critical nozzle, a sonic nozzle, a slit structure, or the like. The diameter of the orifice or nozzle is set to, for example, 10 to 500. mu.m.
As the first control valve 6 and the second control valve 8, valves whose opening degrees can be adjusted arbitrarily, for example, known piezoelectric element driven valves in which a metal diaphragm valve body is opened and closed by a piezoelectric actuator are used. The piezoelectric element drive valve can be adjusted to an arbitrary opening degree by controlling a drive voltage to the piezoelectric element.
In the normal flow rate control mode of the flow rate control apparatus 100, the opening degree of the first control valve 6 is controlled based on the output from the first pressure sensor 3, and feedback control is performed so as to maintain the upstream pressure P1 output from the first pressure sensor 3 at a set value. The first control valve 6 is used as a main flow control valve which is a main valve for flow control. As the first control valve 6, a normally closed valve is used here, but a normally open valve may be used.
On the other hand, the second control valve 8 is mainly used when the flow rate is switched, for example, when the flow rate is increased from zero to a low set flow rate, and is used to perform a flow rate control of a decrement formula to be described later. The second control valve 8 is kept fully open at the time of normal flow rate control other than the time of flow rate switching, or is kept at an opening degree having an opening cross-sectional area at least larger than the opening area of the throttle portion 2. As the second control valve 8, a normally closed valve may be used, or a normally open valve may be used. If a normally open valve is used as the second control valve 8, the drive voltage does not need to be applied during the flow rate zero period and the flow rate increase period, and power consumption can be reduced.
The second control valve 8 may be used for flow rate control other than when the flow rate is increased, for example, may be used for reduced flow rate control performed when the flow rate is decreased to change the flow rate from a high set flow rate to a low set flow rate. Such a flow control method is disclosed in international application No. PCT/JP2019/16763 filed by the present applicant. The flow rate control device 100 according to the embodiment of the present invention is configured to: when the flow rate varies, such as when the flow rate increases or when the flow rate decreases, the second control valve 8 can be used to perform a reduced flow rate control.
In addition, as described above, in the present embodiment, the second control valve 8 and the throttle portion 2 are integrally formed, and constitute the orifice built-in valve 9. The orificium built-in valve 9 is described in, for example, patent document 4, and in the present embodiment, an orificium built-in valve having the same structure as the conventional one can be used. In the orificed valve 9, the valve body of the second control valve 8 and the orifice plate as the orifice portion 2 are disposed in close proximity, and the flow path volume therebetween is considered to be reduced to substantially zero. Therefore, if the orificed valve 9 is used, the characteristics of the rise and fall of the flow rate can be improved. In the case of using the orificed valve 9, the internal volume V between the first control valve 6 and the second control valve 8 is considered to be substantially equivalent to the internal volume between the first control valve 6 and the orificed plate. Therefore, as described below, when the flow rate is controlled by using the above-described internal volume V, there is an advantage that the approximate internal volume V can be easily obtained with relatively high accuracy.
In the orifice built-in valve 9, both the throttle portion 2 (here, an orifice plate) and the second control valve 8 may be provided on the upstream side, but it is preferable that the volume between the throttle portion 2 and the second control valve 8 (here, the space surrounded by the orifice plate, the diaphragm valve body of the second control valve 8, and the valve seat portion) is as small as possible. The orifice built-in valve 9 is a suitable means for minimizing the volume described above.
The flow rate control device 100 described above performs flow rate control based on the principle that the flow rate is determined by the upstream pressure P1 when the critical expansion condition P1/P2 (in the case of argon gas) is satisfied in the normal flow rate control mode. When the critical expansion condition is satisfied, the flow rate Q on the downstream side of the throttle portion 2 is set from Q to K1P1 (wherein, K1A constant depending on the type of fluid and the temperature of the fluid) gives a positive example of the flow Q with the upstream pressure P1. In the case where the second pressure sensor 4 is provided, even when the difference between the upstream pressure P1 and the downstream pressure P2 is small and the above-described critical expansion condition is not satisfied, the flow rate can be obtained by calculation, and the Q ═ K is determined based on the upstream pressure P1 and the downstream pressure P2 measured by the first pressure sensor 3 and the second pressure sensor 4, and the Q ═ K2·P2m(P1-P2)n(Here, K2Depending on the type of fluid and the temperature of the fluidConstant of degree, m, n are exponents derived based on the actual flow rate) can be found.
In the normal flow rate control mode, when a set flow rate signal is transmitted from an external control device or the like to the control circuit 7, the control circuit 7 uses a flow rate calculation formula under a critical expansion condition or a non-critical expansion condition based on the output of the first pressure sensor 3 or the like, and obtains Q ═ K from the above-mentioned formula1P1 or Q ═ K2·P2m(P1-P2)nAnd calculating the flow rate. Then, the first control valve 6 is feedback-controlled so that the flow rate of the fluid passing through the throttle portion 2 approaches the set flow rate (that is, so that the difference between the calculated flow rate and the set flow rate approaches 0). The calculated flow rate may be displayed on a display device as a control flow rate output value, for example.
The flow rate control device 100 of the present embodiment can also perform flow rate control as described below when the flow rate is increased from a state in which the flow rate is zero to an arbitrary first flow rate exceeding zero.
Fig. 2 is a graph showing (a) a set flow rate, (b) a control flow rate, (c) an upstream pressure P1, (d) a driving voltage of the first control valve 6 (also referred to as a first valve), (e) a driving voltage of the second control valve 8 (also referred to as a second valve) in the normally open type, and (f) a driving voltage of the second control valve 8 in the normally closed type, respectively, when the flow rate is increased by the flow rate control method according to the present embodiment.
Fig. 2(d) shows a drive voltage when the first control valve 6 is Normally Closed (NC). On the other hand, fig. 2(e) and (f) show the drive voltages when the second control valve 8 is Normally Open (NO) and Normally Closed (NC). The lower the drive voltage, the smaller the valve opening of the first control valve 6, and the valve is completely closed (closed) when no voltage is applied with the drive voltage of 0. On the other hand, the higher the drive voltage, the smaller the valve opening degree of the normally OPEN second control valve 8, and the fully closed (closed) state is achieved when the drive voltage is maximum, and the fully OPEN (OPEN) state is achieved when the drive voltage is 0 (no voltage is applied). The lower the drive voltage, the smaller the valve opening of the normally closed second control valve 8, and the fully closed (closed) state is achieved when the drive voltage is 0 (no voltage is applied), and the fully OPEN (OPEN) state is achieved when the drive voltage is maximum.
Fig. 2 shows an example in which the set flow rate is increased from 0% to 10%, but the present invention is not limited to this. However, when the target set flow rate after the increase is large, it is considered that the pressure supplied from the primary side after the first control valve 6 is opened is higher than the residual pressure, and overshoot is unlikely to occur. Therefore, the flow rate control method of the present embodiment can be suitably used particularly when the flow rate is increased from 0% to a low set flow rate (for example, 50% or less, typically 20% or less, and particularly about 10%).
Hereinafter, all flow rate values such as the set flow rate and the target flow rate are expressed by a ratio of the rated flow rate value to 100%. When the critical expansion condition is satisfied, the upstream pressure when the flow rate is 100% may be defined as 100% and the upstream pressure may be expressed as a ratio, considering that the flow rate is proportional to the upstream pressure P1.
First, when the flow rate is set to 0% and the gas supply is stopped, the first control valve 6 and the second control valve 8 are completely Closed (CLOSE). However, when the gas flows at a desired flow rate before the gas supply is stopped, even after the first control valve 6 and the second control valve 8 are closed, pressure remains in the flow path between the first control valve 6 and the second control valve 8. In the illustrated example, the first control valve 6 and the second control valve 8 are closed after the gas has flowed at the flow rate of 100%, and the value of the upstream pressure P1 remaining at the flow rate of 0 is 300kPa abs which is high in the present embodiment.
Next, at time t0 shown in fig. 2, the flow rate starts to increase from the state of 0% to 10%. At this time, at time t0, as shown in fig. 2(d), the first control valve 6 is maintained in the fully closed state (closed).
On the other hand, at time t0, as shown in fig. 2(e) and (f), the second control valve 8 is opened, and the operation of adjusting the opening degree thereof is started.
In the state after time t0, since no gas from the upstream side flows in through the first control valve 6 and the second control valve 8 is opened, the residual gas between the first control valve 6 and the throttle portion 2, more specifically, the residual gas between the first control valve 6 and the second control valve 8 flows out through the second control valve 8. Here, the downstream side of the flow control device 100 is evacuated to maintain the downstream side at a vacuum pressure.
At this time, when the opening degree of the second control valve 8 is not adjusted, the residual gas and the residual pressure continue to decrease exponentially with the outflow time, and the flow rate similarly decreases. Therefore, in order to keep the outflow constant at the 10% flow rate, the opening degree of the second control valve 8 needs to be adjusted.
Therefore, in order to keep the 10% flow rate, in the present embodiment, the decrease control mode in which the second control valve 8 is feedback-controlled is switched so that Δ P1/Δ t matches the value set corresponding to 10% based on the output of the first pressure sensor 3. Here, Δ P1/Δ t is a ratio of the change Δ P1 in the upstream pressure P1 output by the first pressure sensor 3 to the time Δ t required for the change Δ P1 in the upstream pressure P1, and corresponds to a rate of decrease in the upstream pressure P1 with respect to time (hereinafter, sometimes referred to as a pressure change rate) or a gradient of pressure decrease.
This is because the flow rate Q of the gas flowing downstream of the second control valve 8 in the state where the first control valve 6 is closed can be expressed as Q ═ α · (Δ P1/Δ t) · V (where α is a proportionality constant and V is an internal volume between the first control valve 6 and the second control valve 8), and if Δ P1/Δ t is constant, the flow rate downstream of the second control valve 8 is also kept constant. In addition, as described above, when the second control valve 8 and the throttle portion 2 are integrally provided as an orifice valve, the internal volume V can be regarded as being substantially equal to the flow path volume from the first control valve 6 to the throttle portion 2. The internal volume V can be obtained in advance from the diameter of the flow path on the downstream side of the first control valve 6. The internal volume V can also be obtained by calculation by a pressure increase rate method by opening the first control valve 6 and closing the second control valve 8 from a state in which the first control valve 6 is closed and the downstream side thereof is kept at the vacuum pressure, and measuring the pressure increase rate (Δ P1/Δ t) when the gas flows into the space of the volume V at a known reference flow rate (for example, disclosed in patent document 5).
The so-called decrement method (disclosed in patent document 6, for example) for obtaining the flow rate Q based on the measurement of Δ P1/Δ t is typically a method for obtaining the flow rate by measuring Δ P1/Δ t after closing the upstream valve while the downstream valve is kept at a low pressure such as a vacuum pressure. More specifically, as described in patent document 6, for example, the flow rate can be determined by Q ═ 1000/760 × 60 × (273/(273+ T)) × V × (Δ P/Δ T). Here, T is a gas temperature (c), V is the above internal volume (l), Δ P is a magnitude of pressure drop (Torr), and Δ T is a time (sec) required for pressure drop of Δ P.
In the present embodiment, Δ P1/Δ t corresponding to a desired flow rate (i.e., a target flow rate after the flow rate is increased, which is a 10% flow rate in this case) is also determined based on a known decrement method, and the residual gas can be continuously flowed at a desired constant flow rate on the downstream side of the second control valve 8 by feedback-controlling the opening adjustment of the second control valve 8 based on the output of the first pressure sensor 3 so that the determined Δ P1/Δ t can be achieved. Further, as is clear from the above equation, since the flow rate also varies depending on the gas temperature T, if Δ P1/Δ T is also controlled using the output of the temperature sensor 5 that measures the gas temperature T, the flow rate can be controlled with higher accuracy.
When the above-described flow rate control by the decrement method is applied to the second control valve 8, the control flow rate increases from zero as the second control valve 8 is gradually opened after time t0, and control for keeping Δ P1/Δ t at a constant value is continued even after time t1 when Δ P1/Δ t reaches a value corresponding to 10% flow rate. During this reduced flow rate control period, the first control valve 6 is kept in the closed state, while the second control valve 8 continuously adjusts the opening degree by feedback control so that Δ P1/Δ t is kept at a constant value based on the output of the first pressure sensor 3.
In the flow rate control of the continuous decrement method, the residual gas flows out at a constant flow rate as the upstream pressure P1 decreases linearly. When the output value of the first pressure sensor 3 is set to the time t2 when the output value decreases to the upstream pressure corresponding to the 10% flow rate (here, 30kPa abs) in the normal flow rate control mode using the first control valve 6, the first control valve 6 is opened at the opening corresponding to the 10% flow rate (the pressure from the first control valve 6 to the inner volume of the throttle section 2 is controlled to the opening of 30kPa abs) at the time t2 in the present embodiment. Thus, the gas is caused to flow from the upstream side of the first control valve 6, and the gas can continue to flow at a flow rate of 10% even after the time t2 downstream of the throttle portion 2 and the second control valve 8. After time t2, the second control valve 8 is kept in a fully OPEN state (OPEN), or in a state of being opened at an opening degree equal to or larger than at least the opening area of the throttle portion 2.
As described above, in the present embodiment, the flow rate control (reduced flow rate control) based on the measurement of Δ P1/Δ t can be performed using the second control valve 8, and the operation can be switched to the reduced flow rate control mode when the flow rate increases, and then to the normal flow rate control mode using the first control valve 6 when the predetermined pressure is reached.
However, in order to perform the reduction flow rate control mode, the residual pressure needs to be large to some extent. This is because when the residual pressure is too low, Δ P1/Δ t cannot be controlled to a value that matches the desired flow rate. In addition, when the target flow rate after the increase is large, the residual pressure may be insufficient for the decrement flow rate control.
In this case, for example, before entering the reduction flow rate control mode, the first control valve 6 may be opened to increase the residual pressure. More specifically, before entering the reduced flow rate control mode, first, the pressure remaining downstream of the first control valve is determined based on the output of the pressure sensor 3 in a state where the first control valve 6 and the second control valve 8 are closed, and when the determined pressure is lower than the pressure corresponding to the target flow rate, the first control valve 6 is opened until the pressure remaining downstream of the first control valve 6 is higher than the pressure corresponding to the target flow rate. Then, by closing the first control valve 6 at a point in time when the output of the pressure sensor 3 exceeds the pressure corresponding to the target flow rate, a sufficient residual pressure can be obtained before entering the reduction flow rate control mode.
Further, when the residual pressure is low as described above, or when the target flow rate after the rise is large, it is considered that overshoot at the time of valve opening due to the residual pressure is unlikely to occur. Therefore, the threshold value of the residual pressure or the threshold value of the target flow rate for entering the reduced flow rate control mode may be set in advance, and when the residual pressure or the target flow rate does not reach the threshold value, the flow rate control mode may be entered not to the reduced flow rate control mode but to the normal flow rate control mode, that is, the flow rate control mode in which the opening degree of the first control valve 6 is adjusted based on the output of the pressure sensor 3. At this time, the second control valve 8 may be controlled to be opened at an opening degree equal to or larger than the opening area of the throttle section 2 or fully opened in conjunction with the opening operation of the first control valve 6.
In another aspect of the present invention, the second control valve 8 may be opened to a predetermined opening degree immediately before entering the reduction flow rate control mode. In this case, a correlation table of the residual pressure, the target flow rate, and the valve opening degree may be stored in a storage device or the like in advance, and the operation of the second control valve 8 may be controlled using the correlation table. When the correlation table is used, the opening degree of the second control valve 8 may be first brought close to the opening degree according to the correlation table, and feedback control may be performed from the opening degree to keep Δ P1/Δ t constant based on the output of the pressure sensor 3.
As items stored in the table, a plurality of parameters such as a gas type, a residual pressure, a control pressure, and the like are considered. In this case, tables corresponding to the respective parameters may be prepared, but a reference table may be prepared, and for example, when the gas type is different, a correction coefficient corresponding to the gas type may be provided to cover the difference in the gas type, and the reference table may be corrected and used. Alternatively, even when the reference table is used without correction, the second control valve 8 can be brought close to the desired opening to some extent, and therefore the load of control can be reduced while improving the responsiveness of the second control valve 8.
As shown in fig. 2(b), according to the flow rate control method of the present embodiment described above, the control flow rate can be rapidly increased in a short time (for example, 0.1 second) from time t0 to time t1, and the gas can be flowed by the residual pressure by keeping the first control valve 6 closed, so that the pressure overshoot is less likely to occur even when the control flow rate is increased to the low set flow rate, and the occurrence of the overshoot can be prevented. Further, by adjusting the opening degree of the second control valve 8, the gas can be stably and continuously flowed at the increased flow rate, and further, after the residual gas is reduced to a predetermined pressure, the gas can be continuously flowed at a desired flow rate by opening the first control valve 6.
Hereinafter, a flowchart of an example of the flow rate control method according to the present embodiment will be described with reference to fig. 3. In the flowchart, the decrement flow rate control mode is executed.
As shown in step S1 of fig. 3, first, at the time of 0% setting, in a state where the first control valve 6 (first valve) and the second control valve 8 (second valve) are closed, the upstream pressure P1, which is the residual pressure, at the time of both valves closing is measured using the pressure sensor 3.
Next, as shown in step S2, it is determined whether or not the measured upstream pressure P1 is equal to or greater than the threshold Pth. If the upstream pressure P1 is equal to or higher than the threshold Pth (yes), the routine proceeds to a decrement flow control mode in step S4. On the other hand, when the upstream pressure P1 is not equal to or higher than the threshold value (no), the first control valve 6 is opened until the upstream pressure P1 becomes equal to or higher than the threshold value in step S3-1, and then the first control valve 6 is closed in step S3-2.
In another embodiment, when the measured upstream pressure P1 does not reach the threshold Pth in step S2, the routine proceeds to the reduced flow rate control mode, and proceeds directly to the normal flow rate control mode in which the first control valve 6 is opened and the opening degree thereof is controlled based on the output of the pressure sensor, as shown in step S6.
When the upstream pressure P1 is very high, the operation proceeds to the reduction flow rate control mode and the flow rate is increased from 0% to 10%. Specifically, the second control valve 8 is opened while the first control valve 6 is kept closed, and the flow path volume between the first control valve 6 and the second control valve 8 (or the throttle section 2) is set to the volume V, and the flow rate control is performed in accordance with Q · (Δ P1/Δ t) · V, that is, the opening degree of the second control valve 8 is controlled based on the output of the pressure sensor 3 so that Δ P1/Δ t is maintained at a predetermined value (a value corresponding to 10% flow rate) as shown in step S4.
Further, as shown in step S5, the output of the first pressure sensor 3 is monitored, and it is determined whether the upstream pressure P1 output from the first pressure sensor 3 reaches a predetermined value, more specifically, a predetermined value corresponding to a 10% flow rate in the flow rate control according to Q1 · P1. If it is determined that the flow rate has not reached the predetermined value (no), the flow control returns to step S4 to continue the opening degree control of the second control valve 8, and the amount-decreasing control mode in which the gas flows at a flow rate of 10% is continued.
When it is determined in step S5 that the output of the first pressure sensor 3 has reached the predetermined value (yes), the control is switched such that the first control valve 6 is opened at an opening corresponding to the 10% flow rate and the second control valve 8 is fully opened or the opening of the throttle section 2 is equal to or larger than the opening, as shown in step S6. This switches to the normal flow control mode. Then, the first control valve 6 can perform feedback control based on the output of the first pressure sensor 3, and by being based on Q ═ K1Flow control of P1 continuously flowing gas at 10% flow.
While the embodiments of the present invention have been described above, various modifications are possible. For example, the above description has been made of the mode of maintaining the first control valve 6 in the closed state after the flow rate increase starts, but the present invention is not limited to this. In the reduced flow rate control mode after the start of the increase in the flow rate, the first control valve 6 may be opened to a constant opening degree smaller than the opening degree corresponding to the target flow rate (for example, an opening degree corresponding to a set flow rate of 5%), and the state in which the gas is allowed to flow at a flow rate lower than the target flow rate may be continued. In this case as well, by adjusting the opening degree of the second control valve 8 so that Δ P1/Δ t maintains a predetermined value based on the output of the first pressure sensor 3, the fluid can flow at the target flow rate on the downstream side of the second control valve 8. Further, if the first control valve 6 is opened slightly during the reduced flow rate control, the first control valve 6 can be opened to a desired opening more quickly when the normal flow rate control mode is switched at time t2, and therefore, the stability of the flow rate control is improved.
However, since the flow rate equation used in the decrement method is typically an equation assuming that the upstream valve (first control valve 6) is closed, if the original flow rate equation is used in a state where the upstream valve is open and the fluid flows into the volume V, the flow rate may not be appropriately controlled. However, if the flow rate flowing into the volume V from the upstream is known, it is considered that the flow rate calculation formula can be used by correcting it. Therefore, when the inflow amount is known, the situation can be substantially the same as the case where the upstream side valve is closed.
In the above description, the embodiment in which the upstream pressure P1 is measured in the state in which both the first control valve 6 and the second control valve 8 are closed in step S1 when the flow rate is increased has been described, but the invention is not limited thereto. The second control valve 8 may be closed when the flow rate is about to increase, and the first control valve 6 may be closed to a slightly open state at an opening smaller than that when the opening of the first control valve 6 is controlled so as to achieve the first flow rate based on the output of the pressure sensor 3. In this case, the first control valve 6 is opened and the second control valve 8 is closed, so that the measured pressure of the pressure sensor 3 increases, but when the initially measured pressure is equal to or higher than the threshold value, or when the increased measured pressure is equal to or higher than the threshold value, the second control valve 8 may be opened to perform the above-described decrement flow control. The above-described slightly opened state of the first control valve 6 may be continued during the decrement flow rate control.
In the above description, the example in which the timing at which the first control valve 6 and the second control valve 8 are fully opened is set to 100% of the set flow rate has been described, but it is not necessarily required, and a state in which the intermediate opening degree is not fully opened may be set to 100%. In the above-described embodiment, the upstream pressure P1 at the flow rate of 100% was set to 300kPa abs, and the upstream pressure P1 at the flow rate of 10% was set to 30kPa abs, but the present invention is not limited thereto, and the upstream pressure P1 is set to various values depending on the set flow rate, flow rate range, fluid type, and the like.
Industrial applicability of the invention
The flow rate control method and flow rate control device according to the embodiments of the present invention can be suitably used when a material gas or the like is supplied in a semiconductor manufacturing process, particularly when the flow rate is increased from zero.
Claims (17)
1. A flow control method is characterized in that,
using a flow rate control device and performing flow rate increase from a flow rate of zero to a first flow rate, the flow rate control device comprising:
a first control valve provided in the flow path;
a second control valve disposed on a downstream side of the first control valve; and
a pressure sensor that measures a fluid pressure on a downstream side of the first control valve and on an upstream side of the second control valve,
the flow control method comprises the following steps:
a step (a) of obtaining a pressure remaining downstream of the first control valve based on an output of the pressure sensor in a state where the second control valve is closed; and
and (b) controlling a pressure remaining downstream of the first control valve by adjusting an opening degree of the second control valve based on an output of the pressure sensor, and flowing a fluid at the first flow rate downstream of the second control valve.
2. The flow control method according to claim 1,
in the step (a), the residual pressure is obtained in a state where both the first control valve and the second control valve are closed.
3. The flow control method according to claim 2, further comprising the steps of:
in the step (a), when the pressure obtained based on the output of the pressure sensor is lower than the pressure corresponding to the first flow rate, the first control valve is opened until the pressure remaining downstream of the first control valve becomes higher than the pressure corresponding to the first flow rate, and the first control valve is closed at a time point when the pressure corresponding to the first flow rate is exceeded.
4. The flow control method according to claim 1,
in the step (a), the first control valve is formed to have a smaller opening degree than an opening degree when the opening degree of the first control valve is controlled to the first flow rate based on the output of the pressure sensor, and the second control valve is opened to perform the step (b) when the pressure obtained based on the output of the pressure sensor is equal to or greater than a threshold value.
5. The flow control method according to any one of claims 1 to 4,
in the step (b), when α is a proportional constant, Δ P1/Δ t is a pressure change rate which is a ratio of a change Δ P1 in the upstream pressure outputted from the pressure sensor to a time Δ t required for the change Δ P1 in the upstream pressure, and V is an internal volume between the first control valve and the second control valve,
the opening degree of the second control valve is controlled based on a signal output from the pressure sensor so that a reduced flow rate Q represented by Q ═ α · (Δ P1/Δ t) · V matches the first flow rate.
6. The flow control method according to any one of claims 1 to 5, characterized by further comprising a step (c) of controlling the opening degree of the first control valve based on the output of the pressure sensor to flow fluid at the first flow rate downstream at a point of time when the output of the pressure sensor decreases to a prescribed value after the step (b) is performed.
7. A flow rate control device is characterized by comprising:
a first control valve provided in the flow path;
a second control valve disposed on a downstream side of the first control valve;
a pressure sensor that measures a fluid pressure on a downstream side of the first control valve and on an upstream side of the second control valve; and
a control circuit that controls operations of the first control valve and the second control valve, and is configured to: the flow rate is controlled by controlling the first control valve and the second control valve based on the signal output by the pressure sensor, and when the flow rate is increased from zero to the first flow rate,
the control circuit performs:
a step (a) of obtaining a pressure remaining downstream of the first control valve based on an output of the pressure sensor in a state where the second control valve is closed; and
and (b) controlling a pressure remaining downstream of the first control valve by adjusting an opening degree of the second control valve based on an output of the pressure sensor, and flowing a fluid at a first flow rate on a downstream side of the second control valve.
8. The flow rate control device according to claim 7, further comprising:
an additional pressure sensor disposed on a downstream side of the second control valve.
9. A flow rate control device is characterized by comprising:
a first control valve provided in the flow path;
a second control valve disposed on a downstream side of the first control valve; and
a pressure sensor that measures a fluid pressure on a downstream side of the first control valve and on an upstream side of the second control valve,
the flow rate control means controls the flow rate on the downstream side based on a signal output from the pressure sensor,
when the control flow rate is changed from a flow rate zero state to a first flow rate, the opening degree of the second control valve is controlled based on the output of the pressure sensor from the state in which the second control valve is closed and the flow rate is zero, so that the opening degree of the second control valve is controlled so that the rate of change of the pressure remaining downstream of the first control valve matches the rate of change of the pressure when the flow rate is discharged from the second control valve reaches the first flow rate.
10. The flow control device of claim 9,
closing the first control valve when the control flow rate is from the zero flow rate state to the first flow rate.
11. The flow control device of claim 9,
the first control valve is controlled to an opening degree smaller than an opening degree corresponding to the first flow rate when the control flow rate is from the state of the flow rate zero to the first flow rate.
12. The flow control device according to any one of claims 9 to 11,
when α is a proportional constant, Δ P1/Δ t is a pressure change rate which is a ratio of a time Δ t required for a change Δ P1 in the upstream pressure outputted from the pressure sensor to a change Δ P1 in the upstream pressure, and V is an internal volume between the first control valve and the second control valve,
the opening degree of the second control valve is feedback-controlled based on a signal output from the pressure sensor so that a reduced flow rate Q represented by Q ═ α · (Δ P1/Δ t) · V matches the first flow rate.
13. The flow rate control device according to any one of claims 9 to 12, further comprising:
an additional pressure sensor disposed on a downstream side of the second control valve.
14. A flow rate control device is characterized by comprising:
a first control valve provided in the flow path;
a second control valve disposed on a downstream side of the first control valve; and
a first pressure sensor that measures an upstream pressure that is a fluid pressure on a downstream side of the first control valve and on an upstream side of the second control valve,
the flow rate control means controls the flow rate on the downstream side based on the signal output from the first pressure sensor,
using the pressure remaining downstream of the first control valve in controlling the flow from a zero flow condition to a first flow,
controlling the flow according to Q ═ alpha · (delta P1/delta t) · V,
at a point in time when the pressure of the first pressure sensor reaches a prescribed pressure,
switching to be based on Q ═ K1P1, where Q is the flow rate, α is a proportional constant, Δ P1/Δ t is the rate of change in pressure of the upstream pressure, V is the internal volume between the first and second control valves, and K is the internal volume between the first and second control valves1P1 is the upstream pressure output by the first pressure sensor, a constant dependent on the fluid type and fluid temperature.
15. A flow control device according to claim 14,
pressure at the first pressure sensor reaches
Based on Q ═ K1At the time point corresponding to the pressure of the first flow rate in the control of P1, the control is switched.
16. A flow rate control device is characterized by comprising:
a first control valve provided in the flow path;
a second control valve disposed on a downstream side of the first control valve;
a first pressure sensor that measures an upstream pressure that is a fluid pressure on a downstream side of the first control valve and on an upstream side of the second control valve; and
a second pressure sensor that measures a downstream pressure that is a fluid pressure on a downstream side of the second control valve,
the flow rate control device controls the flow rate on the downstream side based on the signals output from the first pressure sensor and the second pressure sensor,
using the pressure remaining downstream of the first control valve in controlling the flow from a zero flow condition to a first flow,
the flow rate is controlled based on Q ═ α · (Δ P1/Δ t) · V,
at a point in time when the pressures based on the first pressure sensor and the second pressure sensor reach a prescribed pressure,
switching to be based on Q ═ K2·P2m(P1-P2)nWhere Q is a flow rate, α is a proportional constant, Δ P1/Δ t is a pressure change rate of the upstream pressure output from the first pressure sensor, V is an internal volume between the first control valve and the second control valve, and K is a pressure change rate of the upstream pressure output from the first pressure sensor2P1 is the upstream pressure, P2 is the downstream pressure output by the second pressure sensor, and m and n are indices derived based on actual flow rate, as constants depending on fluid type and fluid temperature.
17. A flow control device according to claim 16,
pressure at the first and second pressure sensors reaches
Based on Q ═ K2·P2m(P1-P2)nThe control of (1) is switched to a point of time corresponding to the pressure of the first flow rate.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2018-120719 | 2018-06-26 | ||
| JP2018120719 | 2018-06-26 | ||
| PCT/JP2019/024323 WO2020004183A1 (en) | 2018-06-26 | 2019-06-19 | Flow rate control method and flow rate control device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN112272809A true CN112272809A (en) | 2021-01-26 |
Family
ID=68987128
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201980032448.2A Pending CN112272809A (en) | 2018-06-26 | 2019-06-19 | Flow rate control method and flow rate control device |
Country Status (6)
| Country | Link |
|---|---|
| US (1) | US11216016B2 (en) |
| JP (1) | JP7369456B2 (en) |
| KR (1) | KR102421587B1 (en) |
| CN (1) | CN112272809A (en) |
| TW (1) | TWI719513B (en) |
| WO (1) | WO2020004183A1 (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US11326921B2 (en) * | 2017-02-10 | 2022-05-10 | Fujikin Incorporated | Flow rate measuring method and flow rate measuring device |
| CN111989635A (en) * | 2018-04-27 | 2020-11-24 | 株式会社富士金 | Flow rate control method and flow rate control device |
| WO2020004183A1 (en) * | 2018-06-26 | 2020-01-02 | 株式会社フジキン | Flow rate control method and flow rate control device |
| WO2021176864A1 (en) * | 2020-03-05 | 2021-09-10 | 株式会社フジキン | Flow rate control device and flow rate control method |
| JP7122335B2 (en) * | 2020-03-30 | 2022-08-19 | Ckd株式会社 | Pulse shot type flow control device, pulse shot type flow control method, and program |
| JP2022029854A (en) * | 2020-08-05 | 2022-02-18 | 株式会社堀場エステック | Flow controller, flow control method and flow control program |
| JP2023080611A (en) * | 2021-11-30 | 2023-06-09 | 株式会社堀場エステック | Flow rate control device, flow rate control method, and program for flow rate control device |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2000136732A (en) * | 1998-11-02 | 2000-05-16 | Toshiba Corp | Gas turbine controller |
| CN102687087A (en) * | 2009-10-15 | 2012-09-19 | 关键系统公司 | Method and apparatus for gas flow control |
| US20140083514A1 (en) * | 2012-09-25 | 2014-03-27 | Mks Instruments, Inc. | Method and Apparatus for Self Verification of Pressured Based Mass Flow Controllers |
| KR20180056710A (en) * | 2015-12-25 | 2018-05-29 | 가부시키가이샤 후지킨 | Anomaly Detection Method Using Flow Control Device and Flow Control Device |
| CN108121370A (en) * | 2017-12-23 | 2018-06-05 | 东北大学 | A kind of investigating method and TT＆C system of vacuum environment gas flow |
| JP2018092622A (en) * | 2016-11-28 | 2018-06-14 | 株式会社フジキン | Piezoelectric drive type valve and flow rate control device |
Family Cites Families (30)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS4933936B1 (en) | 1970-02-20 | 1974-09-11 | ||
| US6782906B2 (en) * | 2000-12-28 | 2004-08-31 | Young-Chul Chang | Time based mass flow controller and method for controlling flow rate using it |
| JP2002341947A (en) * | 2001-05-21 | 2002-11-29 | Mitsubishi Heavy Ind Ltd | Pressure flow rate controller |
| US6913031B2 (en) * | 2001-10-18 | 2005-07-05 | Ckd Corporation | Pulse shot type flow controller and pulse shot type flow controlling method |
| JP2007058352A (en) * | 2005-08-22 | 2007-03-08 | Asahi Organic Chem Ind Co Ltd | Fluid controller |
| JP4743763B2 (en) | 2006-01-18 | 2011-08-10 | 株式会社フジキン | Piezoelectric element driven metal diaphragm type control valve |
| JP4820698B2 (en) * | 2006-07-03 | 2011-11-24 | 株式会社フジキン | Method for detecting abnormal operation of the valve on the downstream side of the throttle mechanism of the pressure type flow control device |
| JP4933936B2 (en) | 2007-03-30 | 2012-05-16 | 株式会社フジキン | Piezoelectric drive valve |
| TWI376581B (en) * | 2007-06-05 | 2012-11-11 | Ckd Corp | Vacuum pressure control system |
| EP2247819B1 (en) | 2008-01-18 | 2022-11-02 | Pivotal Systems Corporation | Method and apparatus for in situ testing of gas flow controllers |
| JP2012060104A (en) * | 2010-08-11 | 2012-03-22 | Toshiba Corp | Power supply controller, plasma processing apparatus, and plasma processing method |
| US8997686B2 (en) * | 2010-09-29 | 2015-04-07 | Mks Instruments, Inc. | System for and method of fast pulse gas delivery |
| US9348339B2 (en) * | 2010-09-29 | 2016-05-24 | Mks Instruments, Inc. | Method and apparatus for multiple-channel pulse gas delivery system |
| JP5848980B2 (en) * | 2012-02-09 | 2016-01-27 | 日立オートモティブシステムズ株式会社 | Brake device |
| JP5960614B2 (en) * | 2012-03-29 | 2016-08-02 | Ckd株式会社 | Fluid control system and fluid control method |
| JP5665793B2 (en) * | 2012-04-26 | 2015-02-04 | 株式会社フジキン | Variable orifice type pressure control flow controller |
| JP5768186B2 (en) | 2012-05-31 | 2015-08-26 | 株式会社フジキン | Build-down flow control device with flow monitor and flow control method with monitor using the same. |
| FR2994455B1 (en) * | 2012-08-10 | 2014-09-05 | Faurecia Sys Echappement | SUPPLY ASSEMBLY FOR A GAS DOSE FLOW, ASSOCIATED METHOD, EXHAUST LINE OF A VEHICLE EQUIPPED WITH SUCH AN ASSEMBLY |
| JP5797246B2 (en) * | 2013-10-28 | 2015-10-21 | 株式会社フジキン | Flow meter and flow control device including the same |
| JP6321972B2 (en) | 2014-01-21 | 2018-05-09 | 株式会社フジキン | Pressure flow control device and overshoot prevention method at the start of the flow control |
| JP6512959B2 (en) * | 2015-06-19 | 2019-05-15 | 東京エレクトロン株式会社 | Gas supply system, gas supply control method, and gas replacement method |
| JP6795832B2 (en) | 2016-07-05 | 2020-12-02 | 株式会社フジキン | Flow control equipment, flow calibration method for flow control equipment, flow measurement equipment and flow measurement method using flow measurement equipment |
| JP6786096B2 (en) * | 2016-07-28 | 2020-11-18 | 株式会社フジキン | Pressure type flow control device |
| US10648572B2 (en) | 2016-07-29 | 2020-05-12 | Fujikin Incorporated | Valve with built-in orifice, and pressure-type flow rate control device |
| US10031004B2 (en) * | 2016-12-15 | 2018-07-24 | Mks Instruments, Inc. | Methods and apparatus for wide range mass flow verification |
| JP7107648B2 (en) * | 2017-07-11 | 2022-07-27 | 株式会社堀場エステック | FLUID CONTROL DEVICE, FLUID CONTROL SYSTEM, FLUID CONTROL METHOD, AND FLUID CONTROL DEVICE PROGRAM |
| KR102314330B1 (en) * | 2017-11-30 | 2021-10-19 | 가부시키가이샤 후지킨 | flow control device |
| CN111989635A (en) * | 2018-04-27 | 2020-11-24 | 株式会社富士金 | Flow rate control method and flow rate control device |
| WO2020004183A1 (en) | 2018-06-26 | 2020-01-02 | 株式会社フジキン | Flow rate control method and flow rate control device |
| WO2021026216A1 (en) * | 2019-08-05 | 2021-02-11 | Ichor Systems, Inc. | Laminar flow restrictor |
-
2019
- 2019-06-19 WO PCT/JP2019/024323 patent/WO2020004183A1/en active Application Filing
- 2019-06-19 KR KR1020207019267A patent/KR102421587B1/en active IP Right Grant
- 2019-06-19 US US16/972,157 patent/US11216016B2/en active Active
- 2019-06-19 JP JP2020527444A patent/JP7369456B2/en active Active
- 2019-06-19 CN CN201980032448.2A patent/CN112272809A/en active Pending
- 2019-06-25 TW TW108122043A patent/TWI719513B/en active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2000136732A (en) * | 1998-11-02 | 2000-05-16 | Toshiba Corp | Gas turbine controller |
| CN102687087A (en) * | 2009-10-15 | 2012-09-19 | 关键系统公司 | Method and apparatus for gas flow control |
| US20140083514A1 (en) * | 2012-09-25 | 2014-03-27 | Mks Instruments, Inc. | Method and Apparatus for Self Verification of Pressured Based Mass Flow Controllers |
| KR20180056710A (en) * | 2015-12-25 | 2018-05-29 | 가부시키가이샤 후지킨 | Anomaly Detection Method Using Flow Control Device and Flow Control Device |
| JP2018092622A (en) * | 2016-11-28 | 2018-06-14 | 株式会社フジキン | Piezoelectric drive type valve and flow rate control device |
| CN108121370A (en) * | 2017-12-23 | 2018-06-05 | 东北大学 | A kind of investigating method and TT＆C system of vacuum environment gas flow |
Also Published As
| Publication number | Publication date |
|---|---|
| WO2020004183A1 (en) | 2020-01-02 |
| KR102421587B1 (en) | 2022-07-15 |
| US20210240208A1 (en) | 2021-08-05 |
| US11216016B2 (en) | 2022-01-04 |
| TW202006490A (en) | 2020-02-01 |
| JP7369456B2 (en) | 2023-10-26 |
| JPWO2020004183A1 (en) | 2021-07-08 |
| KR20200093031A (en) | 2020-08-04 |
| TWI719513B (en) | 2021-02-21 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN112272809A (en) | Flow rate control method and flow rate control device | |
| KR102250967B1 (en) | Pressure type flow control device and flow control method | |
| US11269362B2 (en) | Flow rate control method and flow rate control device | |
| US8033801B2 (en) | Liquid chemical supply system and liquid chemical supply control device | |
| US10386863B2 (en) | Pressure-type flow controller | |
| TWI709013B (en) | Flow control device and flow control method | |
| CN108536180B (en) | Fluid control device and program storage medium for fluid control device | |
| CN114542780A (en) | Fluid control device, control method of fluid control device, and program storage medium | |
| KR20220017838A (en) | Flow rate control apparatus, flow rate control method, and program recording medium recording flow rate control program | |
| CN114545983A (en) | Flow rate control device, flow rate control method, and program storage medium | |
| KR20190134787A (en) | Fluid control system and flow measurement method | |
| JP2020013269A (en) | Flow controller | |
| US20220228896A1 (en) | Pressure control system, pressure control method, and pressure control program | |
| JP2021189514A (en) | Mass flow controller and hunting suppressing method | |
| JP2021096823A (en) | Flow rate controller, fluid controller, flow rate control method, and program for flow rate controller | |
| JP7054297B2 (en) | Program for fluid control device and fluid control device | |
| CN116449879A (en) | Fluid control device, fluid control method, and recording medium | |
| JP2022115176A (en) | Flow rate control device and flow rate control method | |
| JP2004013249A (en) | Gas supply system |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |